A typical hydroelectric generating device known in the art includes a water wheel and a generator whose rotating shaft is connected to the water wheel, with the water wheel and the generator housed in a single casing. The hydroelectric generating device is configured to: provide a water stream, supplied to an end of the casing, to the water wheel; let the water stream flow out of the other end of the casing to drive the water wheel to rotate; and cause the rotation of the water wheel to drive the rotating shaft of the generator to rotate and generate electricity as well as cool the generator housed in the casing using the water stream flowing into the casing. In addition, among hydroelectric generating devices including a water wheel and a generator, Patent Document 1 discloses a hydroelectric generating device whose generator is water cooled.
Furthermore, a typical pump system in the known art, including a pump and an electric motor, is structured so that: a water pump is connected to the rotating shaft of the electric motor, with the water pump and the electric motor vertically arranged; and a power conversion controller (an inverter, for example) for controlling the electric motor is arranged and connected to a side of the electric motor. The pump system is configured to have the water pump arranged in a connecting portion between inlet and outlet pipes, cause the electric motor, powered by electricity, to drive the water pump to rotate, and supply a water stream from the outlet pipe.